When it comes to the market's biggest winners over the past decade, it's hard not to bring Sirius XM Radio (NASDAQ:SIRI) to the table. The satellite radio giant has been a 142-bagger since bottoming out in early 2009, but Sirius XM Radio isn't the only way to cash in on the stock's success. 

We've pitted Sirius XM against other media companies, trying to find out which investment has the better shot at delivering winning results in your portfolio. Let's try something different this time, sending Sirius XM into the ring with Liberty SiriusXM (NASDAQ:LSXMA) (NASDAQ:LSXMB) (NASDAQ:LSXMK), Liberty's tracking shares that own a majority stake in the satellite radio giant but trade at a discount. Don't assume you already know the winner here, as this is a more complicated battle than you probably think.

Eminem on the set of his Shade 45 with his guests.

Image source: Sirius XM Holdings.

Two ways to play

Sirius XM's success is widely known. The 2008 combination of Sirius and XM created a satellite radio monopoly that has rocked the world of a growing number of commuters. We're up to 34.6 million total subscribers at last count, and despite the arrival of the connected car and the long list of streaming apps now available to play seamlessly through your dashboard, Sirius XM keeps climbing in popularity. 

The Sirius XM story is one that fans of low-priced stocks love to tell. The shares traded for as low as $0.05 when it was on the brink of bankruptcy nearly 11 years ago, and now it's a consistently profitable juggernaut that will close out this year raking in more than $1.6 billion in free cash flow. The story that many investors don't know about is that of Liberty SiriusXM, a way to get in on a discount -- but there is a catch.

A big reason Sirius XM didn't fold in early 2009 was that it found a media giant willing to make a big bet on satellite radio. Liberty Media eventually gobbled up a majority stake in the company, and Liberty SiriusXM is the tracking stock that owns a 71.5% stake in Sirius XM.

Sirius XM is commanding a market cap of $31.6 billion, so Liberty SiriusXM's stake is worth $22.6 billion. Liberty SiriusXM is fetching just $15.2 billion on the open market. It also has roughly $950 million in debt independently of Sirius XM's balance sheet, so tack that on to Liberty SiriusXM's market cap to get to $16.15 billion -- a nearly 29% discount. 

Everyone loves a bargain, and it's easy to see why some consider Liberty SiriusXM to be a thinking investor's Sirius XM Radio. I'm going to side with the better-known common stock as the better play, but I have my reasons. The biggest stumbling block is that the tracking stock has always traded at a significant discount to Sirius XM. There are no guarantees that it will ever approach the market value outside of a liquidity event, and even if that did happen there would be some negative implications to both stocks, given the burst in Sirius XM's float. 

Liberty SiriusXM doesn't move in lockstep to the more popular stock it's tracking. Sirius XM is wrapping up its 11th consecutive year of positive returns, but Liberty SiriusXM has had a down year. The discount has also widened in 2019, another year in which Sirius XM has outgained Liberty SiriusXM. There's a lot to like here no matter which route you take to buy into the premium radio provider. It's one of the market's top consumer discretionary stocks. However, Sirius XM is the more reliable play on the platform. Sometimes you have to pay face value for your investments. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.